Hi, Liva. Welcome to English Forums. Thanks for joining us! [<:o)]
A cookout is first of all an occasion. It often has the flavor of a party.
It's usually outdoors - in the back yard, on the patio, at the park, at a campsite, etc.
Meat is typically barbecued over wood coals or on a portable gas grill.
I'm having a cookout at my house this weekend.